1. Field of the Invention
This invention relates to a picture reproducing device for reproducing the information including the compressed picture information presented by the communication or the information recording media, such as a CD-ROM.
2. Description of the Related Art
The picture reproducing device for reproducing the customary picture information, such as the information presented by the CD-ROM, may be roughly classified into two type of devices. One such device is that in which only the picture information, such as the information of letters or pictures to be reproduced, is recorded on the CD-ROM in a pre-set form and is reproduced by a fixed program stored in the reproducing device. Examples of this type of the device include a disc player type reproducing device for reproducing a disc having recorded thereon the information contained in a dictionary, such as an English-Japanese dictionary or a Japanese-English dictionary, or an encyclopedia, and displaying the reproduced information. The other reproducing device is that in which the information to be reproduced is recorded on the CD-ROM and the program for reproducing the recorded information is recorded as an object code for the CPU of the reproducing device, with the CPU in the reproducing device reproducing and executing the program for reproducing the information on the CD-ROM. Examples of this type of the device include the CD-I type picture reproducing device.
On the other hand, a demand has recently been raised for storing moving picture data continuing for a prolonged time on a recording medium such as the above-mentioned CD-ROM. Thus a variety of data compression techniques have been proposed for compressing the moving picture data for reducing the data volume for enabling a large quantity of the moving picture data to be stored on the recording medium. A variety of compressed picture reproducing devices for reproducing data from the recording medium having the compressed picture data compressed by these various data compression techniques stored thereon have also been proposed.
Meanwhile, with these reproducing devices, the menu items or the like as selected by the user are adapted to be displayed in a majority of cases by a graphic screen in the course of the reproduction.
If the menu items are displayed in this manner by the graphic screen, the following problems arise.
First, if the display image for graphic display of the menu items or the like is directly recorded on the information recording medium, the data volume recorded on the information recording medium is increased. If it is attempted to store the moving picture data continuing for a prolonged time on the information recording medium by employing the picture compression technique, the storage capacity is decreased in an amount corresponding to the data volume for the display picture, with the result that the objective of achieving prolonged time recording cannot be accomplished.
While it is possible to transform the displayed picture into e.g. vector data or picture-drawing instructions for recording on the information recording medium for possibly avoiding the data volume in connection with the above-mentioned first problem, it becomes necessary in this case to transform the vector data or the picture-drawing commands into the display data, which raises the second of the above-mentioned problems. The result is the processing speed during the reproduction being lowered and the necessity for a high-performance hardware for executing the processing operations.
Besides, a graphic display circuit is necessitated for performing the graphic display in connection with the first and second problems with consequent rise in production costs for the reproducing device by the graphic display circuit. With the reproducing device having the above-mentioned compressed picture reproducing function, production costs are similarly raised by the addition of the graphic display circuits.